1. Field of the Invention
The present invention relates to a charged particle beam exposure method and exposure device thereof, and more particularly to a charged particle beam exposure method for exposing a narrow space between large sized patterns at high precision, and the exposure device thereof.
2. Description of the Related Art
An exposure method using a charged particle beam, such as an electron beam, enables forming micro-patterns by directly writing them on a wafer. In this writing method, a variable rectangular beam formed by allowing electron beams to pass through two rectangular openings is deflected and irradiated at the drawing position on the wafer, so that the pattern is drawn, or the electron beam is passed through a block mask corresponding to a predetermined repeat pattern, and is deflected and irradiated at the drawing position on the wafer, so that the pattern is drawn. The block mask normally corresponds to the repeat pattern, and is used for drawing a repeat pattern comprised of lines and spaces, for example. A block mask is disclosed, for example, in Japanese Patent Application Laid-Open No. H4-100208.
In the electron beam exposure method, a problem with the displacement of development patterns caused by a proximity effect has been noted. Particularly due to the influence of forward scattering and backward scattering on the resist layer when an electron beam is irradiated, the pattern width increases in an area where the pattern density is high, and the pattern width decreases in isolated patterns where the pattern density is low. In order to suppress the influence of the proximity effect, a correction of the exposure pattern, a correction of the exposure dosage and an addition of an auxiliary exposure have been proposed. For example, these proposals are disclosed in Japanese Patent Application Laid-Open No. 2001-52999 and in No. 2000-323377.